This invention relates to an invalid lifting device and more particularly to such a device for lifting an invalid from a seated to a substantially standing position, especially but not exclusively as part of a toileting procedure.
Lifting devices for lifting an invalid (which term includes infirm, disabled and elderly persons) from a seated to a standing position nowadays generally make use of a sling which is passed around the back and below the armpits of the invalid. The sling is attached to two laterally spaced sling attachment points on a lifting arm which is pivoted, typically by a motor driven linear actuator, relative to a mast upstanding from a mobile chassis to raise the shoulders of the invalid along a generally arcuate path.
According to the present invention there is provided an invalid lifting device comprising a mobile chassis, a lifting mechanism and a sling connectible to the lifting mechanism to at least assist in raising a seated person to a standing or substantially standing position, wherein the lifting mechanism comprises a lifting arm, an actuating device operative to raise and lower the lifting arm, the lifting arm being pivotable about first and second horizontal axes, the first horizontal axis being substantially fixed and being further from a projecting end of the lifting arm than the second horizontal axis, and means defining a guide path along which the second horizontal axis is caused to move as the actuating device raises and lowers the lifting arm.
Preferably, the guide path is generally upwardly inclined in an in use direction away from the person being lifted. In one embodiment, the guide path may be a rectilinear guide path. This has the effect of flattening out the arc through which the end of the lifting arm distal from the horizontal axes would otherwise pivot to thereby mimic the way in which a person stands when lifting himself from a seated position using downward pressure of his hands on the armrests of a chair. Alternatively, the guide path could be a curved guide path and, in this case, it could be an S-shaped or substantially S-shaped guide path so that the person being lifted can be initially moved generally forwards and then moved generally upwards.
Preferably, the lifting device further comprises arm supporting means for supporting the arms of a person to be lifted, the arm supporting means including at least one hand grip. In this case, preferably, the lifting mechanism comprises two arms which are pivotably connected to the arm supporting means. These two arms could form a parallelogram linkage, but are preferably arranged so as to move the arm supporting means from a position in which it is upwardly inclined in an in use direction away from a person to be lifted to, or towards, a position in which it is substantially horizontal as the arm supporting means is raised by the lifting mechanism. This has the advantage that the lifting mechanism can raise and lower a taller person to a standing or substantially standing position than would otherwise be the case with lifting arms of the same length.
Preferably, the invalid lifting device further comprises at least one footrest and knee abutment means above the at least one footrest to support the knees of a person being lifted. The knee abutment means may be mounted for pivotable movement from a vertical or substantially vertical position to an upwardly inclined position in an in use direction away from the person to be lifted against the urging force of spring means. This allows the knees of the patient to move slightly forwards as the patient is lifted, the spring means urging the knee abutment means and the knees of the person being lifted rearwards as the person reaches a standing or substantially standing position.
The knee abutment means and the at least one footrest may be removably supported by the chassis. With the footrest or footrests removed, the lifting device can be used as a rehabilitation aid.
Preferably, the arm supporting means comprises two arm supports. These may be mounted on an inverted U-shaped bracket which is supported by the lifting mechanism. An adjustable strap may be provided between the free ends of the arms of the inverted bracket to prevent a person falling into the bracket. Each arm support is preferably generally L-shaped to support the forearms and at least part of the upper arms of a person to be lifted. In this case, the position of the hand grips may be adjustable so that the elbow of the person to be lifted can rest in contact with the junction between the two limbs of the generally L-shaped arm supports. The arm supports may be provided with releasable straps for holding a person""s arms firmly in place in the arm supports. The arm supports may be shaped to cradle the person""s arms.
Advantageously, the lifting sling has a cord at each end and the inverted U-shaped bracket is provided with two jamb cleats for receiving the two cords, respectively. This allows the effective length of the sling to be adjusted.
Preferably, the lifting device further comprises a support structure upstanding from the chassis, the means defining the guide path being supported between the chassis and the support structure. In this case the support structure may also support means defining said first horizontal axis. The support structure may also support a handle by which an attendant can wheel the lifting device along the floor.
The invention will now be more particularly described, by way of example, with reference to the accompanying drawings.